Supplementary Information Schedule of Cash Paid for Interest and Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest paid	$ 538	$ 467	$ 477
Income taxes paid, net of refunds	87	161	331
Currency Devaluation Charges	0	41	$ 85
Capital Lease Obligations Incurred	24	$ 25
Held-to-maturity Securities	$ 50